Windows DLL security flaw impacts hundreds of applications

Security researchers warn a flaw in the way Windows handles DLL (dynamic-link library) and related files likely affects hundreds of popular applications. The flaw was found to affect iTunes last week, and since its discovery dozens of reports have hit the web of programs that are impacted by the bug, including Microsoft software like Office 2007 and Windows Live Mail, but also popular 3rd party software such as Firefox 3.6.8, Foxit Reader, uTurrent and many other tools.

Microsoft acknowledged in an advisory on Monday a type of attack mechanism known as DLL preloading, or binary planting and said that while it is not new it does have a new remote-attack vector. Malicious code can now be planted on a network share instead of just on a local system, making it much easier to attack vulnerable systems by duping people into clicking on malicious Web links or opening malicious documents.

Security firm Acros disclosed the issue last week after finding that it affects iTunes, and Rapid7 Chief Technology Officer HD Moore published additional information about it this week here and here. Moore, creator of the Metasploit database and framework, also released a tool to test whether applications are vulnerable.